Abstract
Wind turbine towers affect the visual appearance of the landscape, as an example in the touristic woodland of Dalecarlia,
and the fear is that the visual impact will be too negative to the important tourist trade. The landscape analysis,
developed by municipalities around Lake Siljan, limited expansion of wind power, due to the strong visual impression of
wind turbine towers. In order to facilitate the assessment of the visual impact of towers a view, from Tällberg, over the
ring of height on the other side of Lake Siljan, has been photographed every ten minutes for a year (34,727 images, about
65% of the possible number during a year). Four towers are possible to see in the photos, three of them have been used in
the assessment of visual impression. This contribution presents a method to assess visibility of wind turbine towers from
photographs, describing the measuring situation (location and equipment) as well as the analytical method and results of
the analysis.
The towers are possible to see in about 48% of analyzed images taken during daytime with the used equipment. During
the summer (winter) months the towers were apparent in 49% (46%) of the images. At least one red warning light was
possible to see on towers in about 66% of the night images.
One conclusion of this work is that the method to assess the visibility within digital photographs and translate it into the
equivalent of a normal eye can only provide an upper limit for visibility of an object.
